Next time a new GSM/GPRS-Modul will be available direct from Arduino. It's a cooperation with Telefonica. Pre-series samples of the board were presented on the "Campus Party Berlin" in August 2012. Unfortunately the Bluevia / Telefonica site reports only "coming soon" for "buy shield & sim" https://bluevia.com/en/page/tech.arduino and there is no exact date when the shield will be available.

Is the library and other stuff compele new or is the shield compatible to other libraries? Seems that nearly every shield has its own library. :-/

See also:http://www.engadget.com/2012/08/24/arduino-gsm-gprs-shield-gets-helping-hand-from-telefonica/ andhttp://www.heise.de/hardware-hacks/meldung/Campus-Party-Arduino-stellt-GSM-GPRS-Modul-vor-1674914.html

FWIW, I have had very good luck with the Seeedstudio version. Geekonfire also has a model.

Whatever module you want to consider, research the underlying chip and libraries! For the sim900 there are a number of libraries and examples out there that you can follow along. The AT manual also gives you the commands you'll need to use in order to start a GPRS connection, send an SMS, etc

Also, depending on where you live, it might make sense to use a M2M Sim card, ie one designed specifically for applications like this one. I had good luck with the unit from embedded works.

I asked BlueVia / Telefonica about the deliver date of the new Telefonica-Arduino-GSM shield again. Announcement / purchase see: https://bluevia.com/en/page/tech.arduino

The really friendly support told me they had some problems with the launch and the release date got delayed. If everything goes as expected, the new release day is the 22nd October. I assume 2012, the year was not specified explicit. :-)

Again one month is gone and still no shield available neither by bluevia nor by an other distributor. :-/ Will this shield also be available in the official Arduino store http://store.arduino.cc (without SIM)?

At http://labs.arduino.cc/GPRS/Index David Cuartielles and Gianluca Martino are mentioned as key people in the GPRS shield development and they are also labeled as "co-founders of the Arduino project" - so I thought the hard- and softwarepart would be covered by Arduino people. But perhaps this is an old level of information. ;-)

Now - 23rd Dec - the "coming soon" bage on the bluevia website is gone and the buy button is linked to the Arduino store. But there is no product page, no price, no order info for the GSM shield. Has anybody from the Arduino team further information what's going on in this case?